The
final
stitch
of
the
second
bartack
must
be
mode
in
the
middle
of
the
bar
always (see Section
36).
If the last stitch lies too far to the right, the
machine has stopped too early
and
tripping segment 14 must be moved
to the left accordingly. Conversely, if the
last
stitch lies too far to the left,
the tripping segment must be moved to the right in order to make the
machine
stop
earlier.
Note
that
stop tripping segment 14 must be
adjusted
only within certain
narrow
limits
as,
otherwise,
retiming
of
all
other
motions controlled by
the
feed
cam
may
become
necessary. For this reason,
we
recommend
that
you check first
whether
raising or lowering the position of tripping dog 12
will
suffice
to
make
the
machine
stop
sooner
or
later.
This
adjustment
calls for
great
care
since
setting
tripping
dog
12
too
high
would
cause
the
rear
end
of
tripping fever 3 to
be
swung up too
far
and
the machine to
be
stopped
abruptly
rather
than
being
shifted
to low
speed
first.
35.
Adjusting
the
Bar
Tripping
Segment
The tripping
segments
which
are
mounted
on the
back
of the
feed
cam
and
control
the
width
of
the
bartacking
stitches
have
elongated
slots
and
can
be
adjusted
as
required.
The tripping
segment
for the
first
bar
is
secured
by
screws
23
and
24,
that
for
the
end
bar
by
screws
25
and
26 [Photo 35).
After
slackening
these
screws,
both
bar
tripping
segments
can
be
adjusted
so
that
the sewing
of
the
bars
will
commence
at
the
proper
time
and
in
conformity with the feeding motion.
The
tripping
segment
for
the
first
bar
should
be
adjusted
in such a
manner
that
the
first
bar
will
not
be
sewn
until
after,
the first
parallel
is finished
in
order
to
avoid
displacing the first
bartacking
stitches to the left.
The tripping
segment
for the
second
bar
should trip the machine
early
enough to ensure
that
the first stitches of the first parallel will be comple
tely
covered
and
that
a
neat
appearance
of
the
buttonhole
will
be
obtained.
36.
Adjusting
the
Needle
Bar
Zero
Lug
Lug 27
(Photo
22) on
the
top
of
lever
H
permits
to
adjust
the
sideways
motion
of
the
needle
bar
in
relcjtion
to
the
center
line
of
the
buttonhole
for making the tying stitches in the
end
bcwtack.
In
order
to
enhance
the
appearance
of
the
buttonhole,
the
last
tying
stitches
must
be
made
in the
center
of
the
end
bartack.
When
making
these
stitches
there
must be
absolutely
no
sideways
motion
of
the
needle
bar.
The side
ways
motion of the
guide
roller for the
needle
bctf vibration is thus
checked
by lug 27
when
it
has
reached
a
position
conforming to the
zero
(center) line
of
the
buttonhole.
44
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